The present invention relates to automotive wheels of a two piece construction and, in more particular, to wheels with tubeless tires used on Karts for racing or similiar activities. The unique structure and assembly of the wheel and tires allows easy assembly to a structure specifically designed to maintain inflation of the tire.
Wheels used on vehicles used in the sport of Go-Karting are commonly comprised of two rims bolted together. The tires applied to these rims may be either solid, or pneumatic tubed or tubeless tires. In recent years the trend has been toward greater use of tubeless tires.
When tubeless tires are used, means must be established to insure the assembly remains airtight. Such as assembly usually requires at least three seals The first seal is at the tire and rim interface. This seal is brought about by the cooperating design of the rim edge and the tire bead. The second seal, between the valve stem and the rim, is effected by an interference fit of the stem into a hole in the rim.
The third seal occurs between the two wheel halves. There are presently several methods to accomplish this seal but each of these methods has shortcomings. These methods include applying a film of RTV silicone material to the faces of the wheel parts which are then joined, applying a rubber gasket to the mating surfaces, combined use of rubber cement, bolts and an O-ring placed around the wheel halves at their outer intersection, or placing between the wheel halves a plate having a circular groove in each of its faces with an O-ring placed in each of the grooves.
Applying a seal of RTV silicone material or rubber cement between the wheel halves is messy, may not produce a consistent seal and must be allowed to dry before the tire is inflated. Also it must be removed after each use and then reapplied before each reuse. Use of a solid rubber gasket between the wheel halves may result in leaks at high pressure. Also shifting of the rim halves is a common problem. Use of a plate with gaskets or O-rings on each surface results in a wheel assembly much thicker and heavier than the present invention. This requires mounting a wider tire with a smaller circumference thus necessitating a new gearing arrangement. Wider wheel dimensions also reduces ground clearance thus increasing the possibility of equipment damage.
Several patents have addressed the problem of constructing an airtight wheel assembly. U.S. Pat. Nos. 3,826,538 and 4,223,952 disclose products which utilize a disc with grooves on the two surfaces thereof and an O-ring in each groove. In the '538 patent this disc, which also incorporates an integral cylindrical collar to act as a centering means, is used with two different, specially designed wheel halves. The wheel of U.S. Pat. No. 4,123,112 also requires a specially designed rim half with a groove in an inner surface for accommodating an O-ring. In U.S. Pat. No. 4,424,842 a rubber sealing ring is bonded directly to an inner surface of one of the wheel halves.